Pulsed loads occur in many battery-powered portable devices and the peak current may be many times the resting current. When the battery is nearly flat or is old, its' effective internal resistance tends to increase, and it is less able to supply peak current demand without the device cutting out. Heavy load pulses generally also cause a large voltage drop when they occur, and this may be detrimental to the battery. Lithium-ion batteries are particularly susceptible to damage in this way.
As a result, pulse loads invariably reduce battery run-time as the load will have a minimum threshold supply voltage required at all times. When the load pulses and that voltage drop below the minimum threshold, the electronic device must shut down as the voltage regulating circuitry is no longer able to supply the necessary voltage to run key circuits. However, at this time there may be useful energy remaining in the battery.
Moreover, some portable devices include protection circuitry that shuts the device down if the current drawn from the battery exceeds a predetermined threshold. While this circuitry is designed to protect the battery, it also results in shut down of the device when the peak current, although being over the threshold, was so for only a short period. This then requires the device to be restarted and, in some, cases, reconfigured. For mobile telephone and personal computing applications this is a source of frustration to users.
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.